获取客户端ip

 public static string GetClientIP()
       {
           string result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
           if (null == result || result == String.Empty)
           {
               result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
           }

           if (null == result || result == String.Empty)
           {
               result = HttpContext.Current.Request.UserHostAddress;
           }
           return result;
       }